A movie clip from the film 'The Terror' is shown (the climatic flooding scene at the end featuring actors Boris Karloff, Dick Miller, Jack Nicholson, etc.). The clip ends with the final fade out and it is being shown in a small screening room somewhere in Hollywood. The elderly star of the film, Byron Orlock (Boris Karloff), tells the producer Marshall Smith (Monty Landis) that he has decided to retire from acting because he considers his performance no longer frightening in mainstream society. Marshall and the film's director Sammy Michaels (director Peter Bogdanovich) try to convince him to appear in their next film, but Orlok refuses and plans to return to his native England to live out the rest of his days, and refuses to even read the new script that Sammy gives to him. Orlok walks out with his young secretary Jenny (Nancy Hsueh), whom is Sammy's current girlfriend. Sammy follows him outside to persuade him to stay in Hollywood, but Orlok tells Sammy that he considers himself to be an anachronism because people are no longer frightened by horror pictures. "The world belongs to the young. Let them have it", says Orlock.Across the street, a young man named Bobby Thompson (Tim O'Kelly) is seen buying a high-powered semi-automatic .303 caliber hunting rifle and pays with it by check. He goes out to the parking lot to his white convertible and places the newly purchased rifle in his car truck which has more then a dozen firearms of various calibers. Bobby drives along a freeway listening to the car radio and munching on Baby Ruth candy bars. He arrives home in a suburb of the San Fernando Valley where he lives with his wife Ilene (Tanya Morgan) and his parents and has dinner with them.Across town, Orlok is dining with Jenny at a local restaurant when his manager Ed Laughlin (Arthur Peterson) arrives and tries to persuade him to stay in town at least for a few days to attend the premier of 'The Terror' at a local Racine drive-in theater the following evening. But Orlok refuses and even refuses to speak to Marshall over a phone that Ed tries to set up.After dinner, Bobby and his father go out to a shooting range where they shoot at tin can targets. Bobby has a keen talent from shooting guns apparently due to his recent military service. Since Bobby still lives with his parents, its convenient for him and his father, Robert Thompson Sr., to go out shooting together. While his father is setting up more tin targets, Bobby, for some odd reason points his rifle at his father seemingly intent on shooting him. Robert Thompson sees Bobby aiming the rifle at him and orders him to put the rifle down, because pointing a gun a people goes against everything he has taught his son.That evening, Orlok is in his hotel suite with Jenny who is setting up his schedule for his return to England the following day. Jenny also tries to persuade Orlok to stay at least for the premier of his latest film, but Orlok tells her that he is through with the movie business and still refuses to read Sammy's script. Orlok then sends her home while he stays alone in his room to watch TV.At the Thompson house that evening, the whole family is watching TV together when Ilene says that she has to go to her night job as a switchboard operator. Bobby follows her to the bedroom and wants to talk to her saying that he has not been feeling well lately and has been getting "funny ideas". But since she is late for her job, she tells him that she doesn't have time to talk and leaves. He asks her not to take his car but take her mother's to work and she agrees. After Ilene leaves and his parents go to bed for the night, Bobby goes to his car and takes out one of his guns, a .45 caliber semi-automatic pistol before returning to the house.At Orlok's hotel room, he orders room service and watches himself on one of his old movies 'The Criminal Code' that is playing as a late-night movie. Sammy arrives and demands that Orlok hand over his script and they both watch the movie together. Over drinks, Sammy again tries to convince Orlok to appear in his latest film because the script that he wrote will cast Orlok as a real-life person rather then a bogeyman. But the bitter Orlok announces that he is still fed up with the film business and shows Sammy that people are more frighted by the latest newspaper headings about crimes committed by random people then horror films. Sammy gets so drunk that he attempts to leave, but collapses and Orlok puts him in his own bed and soon afterwords also collapses drunk next to Sammy.Meanwhile at the Thompson house, Bobby is sitting alone in his bedroom chain smoking when Ilene returns home. His tone of voice is now very cold and he asks her not to turn on the lights because he has a headache. When she asks him what he wanted to talk to her about and why he is perplexed, he no longer wants to talk and asks her to go to bed.The next morning, after his father has apparently left for work, Bobby types out a note and when Ilene walks in the room, he suddenly takes out his .45 caliber gun and violently shoots her dead. When Bobby's mother runs into the room, he shoots her dead too. He then shoots an unfortunate grocery delivery man who enters the house. Bobby hides the bodies in rooms through the house, hides the bloodstains and leaves, leaving behind a note saying that he has killed his wife and mother and will continue killing until he is caught or killed.In Orlok's hotel suite, a hung-over Sammy wakes up and sees a sleeping Orlok next to him and jumps, waking him up. Sammy says that he was having a nightmare and woke up to see Byron Orlok. As Orlok gets up to answer a knock on his front door, he passes a mirror and he too jumps from his own reflection. Jenny has arrived with Orlok's internary with his airline tickets to New York as well as his tickets for the ship to take him back to England. However, Orlok finally agrees to make the final promotional appearance at the Racine Drive-In that evening for the premier of his latest film.Across town, Bobby arrives at another gun store and asks for 300 rounds of ammunition for his new rifle as well as box of 12-gauge buckshot for his double-barreled shotgun. Despite the fact that Bobby looks a little jittery and of the unusually large quantity of ammunition requested, the clerk sells him the ammunition. When the clerk asks Bobby about the order, Bobby tells him that he is going out to "shoot some pigs."In Orlok's hotel suite, he, Jenny, Sammy along with a brash radio disk jockey named Kip Larkin (Sandy Baron) discuss his appearance at the drive-in theater for that night and Orlok decides to reherse to them a ghost story that he plans to tell after the movie premier.Meanwhile, Bobby drives to an industrial center and after parking his car, pulls out of the trunk all of his guns in a large pouch and enters an abandoned amusement park that sits next to an oil storage tank facility where he scales a cynderblock wall and climbs up the stairs of one of the oil tanks that sits alongside a busy freeway. Bobby lays out all of his rifles and pistols that he brought with him as if displaying them for himself and then eats a sandwich and drinks soda pop that he also brought before taking am with his new high-powered rifle at motorists traveling along the road and opens fire, killing and/or wounding many in which some cars veer off the road. An oil company worker investigates the shooting, but Bobby kills him too with a blast from his shotgun as he is reloading. When Bobby hears police sirens and sees police cars approaching on the freeway, he grabs most of his guns and runs down the stairs and back to his car, but drops several of his weapons including his .45 pistol, an unused .44 magnum revolver, as well as his shotgun and a rifle and some boxes of ammunition. As Bobby drives away, a police car appears and give chase, but he eludes it by driving into the very same drive-in theater that is showing Orlok's 'The Terror' for that night. After reloading and having a meal from the concession stand, Bobby carries his remaining guns in his US Army pouch and walks through a door leading to the big screen.When it gets dark and the movie finally goes on, Bobby climbs up the structure and begins to shoot the viewers through a small hole in the screen. He first shoots a man in a telephone booth and then shoots people in their cars, on by one. He even shoots and kills the projectionist. Orlok arrives for his special appearance and the limo parks close to the screen. Meanwhile, many viewers start to leave because they realize that there is a sniper present. A traffic jam ensues. When Bobby pauses to reload, he accidentally knocks over his last few boxes of ammunition. Panicking, Bobby climbs down the screen and tries to retrieve the ammo from a drainage but without success.Some male viewers take guns from the trunks of their cars and charge towards the screen. Seeing the vigilante mob approach, Bobby runs to an area to the side of the screen and opens fire randomly. One of his shots seriously injures Jenny as she gets out of the limo. The police soon arrive as does Sammy and they try to find both Orlok and the sniper. Orlok angrily walks towards the screen as Bobby finally runs out of ammunition for his rifle and opens fire with one of his smaller pistols. He gets confused when he sees the Orlok character on the drive-in screen walking towards him and sees the real Orlok walking to him as well. Bobby first shoots Orlok, but misses and only gazes his forehead with the bullet. Bobby takes aim and shoots at the Orlok on the big screen. Blinded by police searchlights zeroing in on him, Bobby fires widely until he runs out of ammo. When Bobby takes out another one of his pistols, Orlok rushes up and knocks the gun out of Bobby's hand with his walking cane and beats Bobby with it as well as literally slapping him into submission. Bobby then cowers in fear as Orlok says, "Is that what I was afraid of?" Two policemen run up to the screen and arrest Bobby. As he is being led away, Bobby says to his police captors, "I hardly ever missed, did I?" Bobby is taken away in a police car while Sammy tends to Orlok and takes him away in his limo as the crowd of people and cars file out of the drive in theater.The final shot shows the deserted drive in theater the morning after which is now empty, except for Bobby's white car sitting alone in the empty lot as the end credits silently roll.